F-35 airborne again but won't fly at air show

Dan Freedman

Updated 8:18 pm, Wednesday, July 16, 2014

WASHINGTON --The Pentagon has lifted its order grounding the futuristic F-35 Joint Strike Fighter, permitting flights with limitations while technicians continue investigating a series of engine problems.

But Defense Department officials canceled the stealth fighter's scheduled appearance this weekend at the Farnborough Air Show in England, fueling critics who wonder if the $400 billion fighter is turning into a procurement disaster.

Pentagon officials told reporters at Farnborough that an "excessive rub" of an engine fan blade was a key factor in the incident in which the F-35 caught fire after takeoff. But inspections of all F135s"'97 in total "'showed no other engines with the same problem.

The fighter, still technically in its developmental stage, was taken off the flight line July 3 after one of the aircraft developed an oil leak and another caught fire after takeoff.

Under terms announced by the Pentagon, the F-35 can fly again with limitations on speed and angle of attack. Also, flights are limited to three hours, after which the front fan section of the F135 engine -- manufactured by East Hartford, Connecticut-based Pratt & Whitney -- must be inspected with a device that permits a close look at hard-to-reach areas.

The three-hour limit played into the Pentagon's decision not to send the aircraft across the Atlantic to the Farnborough Air Show.

The F-35 "is not the first aircraft to have problems like this; it's not going to be the last," said Rear Adm. John Kirby, the Pentagon's chief spokesman. "We're confident we're going to get through this."

After the two incidents earlier this year, Pratt & Whitney sent technicians to assist the Pentagon in figuring out what went wrong. Pratt & Whitney, with 9,000 employees in Connecticut, produces the F135 at plants in Middletown, Conn., and West Palm Beach, Fla.

While other elements of the F-35's 13-year development history forced production delays and cost overruns, the F135 engine performed with reasonable consistency. Mission system software that controls the aircraft's war-fighting capabilities proved problematic, but "flight science testing" -- involving its basic flying capacity -- was on schedule, according to a Government Accountability Office report last March.

That began to change last year. The aircraft was grounded twice last year to fix engine fan blades and leaky fuel hoses.

"We have great confidence in the F135 engine powering the F-35," said Pratt & Whitney spokesman Matthew Bates. "We have worked very closely with DoD and the Services to return the aircraft to flying status, and we will continue to work towards resolving the issue so that the aircraft can resume operations within a broader flight envelope.''

This year's mishaps could not have come at a worse time. The F-35 had been expected to wow the crowds of spectators and aviation industry executives who flock to Farnborough -- Europe's premier aviation event. It was to be the fighter's international debut, a critically important event since it has been developed in cooperation with eight international partners -- Great Britain, Italy, the Netherlands, Turkey, Canada, Australia, Denmark and Norway.

"Hopefully this is one of several hiccups the aircraft has gone through, and not the start of a major trend," said Richard Aboulafia, an aviation analyst with the Teal Group in Alexandria, Va. "The timing is very bad, but it's hardly a serious blow."